ANDROID: KVM: arm64: Fix host_stage2_pte_is_counted()

All valid host mappings are erroneously considered "counted" because
KVM_HOST_S2_DEFAULT_MASK mistakenly drops bit KVM_INVALID_PTE_LOCKED
(bit 10). Not only is this unnecessary, because the lock flag is only
used in invalid ptes, it means that comparisons with
KVM_HOST_S2_DEFAULT_MEM_PTE and KVM_HOST_S2_DEFAULT_MMIO_PTE can never
succeed.

Fix this by incorporating bit 10 back into KVM_HOST_S2_DEFAULT_MASK.

Bug: 278749606
Change-Id: Ic8126e763e319e3ac9ae066d975b3ac48b15f60f
Signed-off-by: Keir Fraser <keirf@google.com>